Aeration of the middle ear cleft is necessary to optimize hearing, to maintain tissue health and function, to prevent middle ear infection or fluid accumulation (OME), and to avoid pain when changing ambient external pressure. Significantly, many individuals, particularly children, are unable to electively move air from the nasopharynx to the middle ear.
The ear is divided into three anatomic and physiologic segments. The most lateral segment is the external ear, a skin lined passage extending from the exterior into the temporal bone of the skull, and terminating at the tympanic membrane.
The middle ear cleft is formed embryologically as an outpouching of the upper respiratory tract or nasopharynx within the temporal bone and communicates with the nasopharynx via the Eustachian tube. It consists of an air-filled cavity bounded laterally by the tympanic membrane and posteriorly by the mastoid cavity, an air reservoir with which it communicates through the antrum. The middle ear, or mesotympanum, contains three bones or ossicles connected in a chain between the tympanic membrane and the oval window, the lateral aspect of the cochlea or inner ear. The Eustachian tube is closed or collapsed in its resting state. Hearing is optimal when the middle ear is air-filled at ambient pressure.
The inner ear consists of the cochlea and the vestibular apparatus which are responsible for hearing and balance, respectively. These organs are connected directly to the central nervous system.
In the normal healthy individual, the air in the middle ear is maintained at the ambient pressure by insufflation though the Eustachian tube by momentary opening about every third time the individual swallows. No voluntary action is necessary to replenish air. This is necessary as the air and air components within the cleft are absorbed by the mucosal lining of the ear. Failure to renew the ambient pressure leads to various disease states.
A number disease conditions are observed that directly relate to abnormal Eustachian tube function. Almost all of these conditions relate to the individual's inability to open the normally closed tube either involuntarily or voluntarily to renew the middle ear ventilation, a state which may be acute (e.g. infection, allergy, etc.), chronic (anatomic abnormalities such as cleft palate or neurologic conditions) or developmental (e.g. immature physiology and inefficient musculature before skull base growth occurs). When the Eustachian tube ceases to function properly, the residual air in the middle ear is absorbed by the cavity lining (mucosa). This reduces the pressure in the middle ear below ambient (i.e. "negative pressure"), and disease may then be induced. The following are a few conditions that may result:
Otitis Media with Effusion: This is the most common pathological condition in children under two years of age. In the acute process, an upper respiratory infection in the nasopharynx hinders normal Eustachian tube function. Bacteria from this region migrate to the middle ear where fluid has been secreted in response to the negative pressure and an acute process is established resulting in the classic earache with fever and hearing loss. In chronic dysfunction, many complications can occur, including stretching of the eardrum, formation of pockets, cholesteatoma formation, hearing loss, and destruction of the ossicles or perforation of the tympanic membrane.
Barotrauma: The changing of the ambient pressure on the body requires pressure equalization into the middle ear cleft. Inability to equalize pressure results in pain on descent in commercial aircraft or upon diving into water, thus resulting in pain and possible rupture of the tympanic membrane.
The Eustachian tube can be opened voluntarily and the middle ear ventilated in most conditions by forcing air through it. This act requires a patent Eustachian tube and an intact neurologic system. Aeration of the middle ear may be accomplished with a relatively passive maneuver as simple as a yawn, but more force is generated by actively pushing air up the Eustachian tube by occluding the nose and mouth, followed by swallowing. Compression of the air in the pharynx by the squeeze of swallowing pushes air into the tube. Likewise, forcefully exhaling or blowing against a closed nose and mouth will achieve the same result. It is this concept that is assisted by the present invention without the use of an outside energy source, as discussed later in greater detail.
Before the turn of the century, Proetz described a method for physicians to inflate the middle ear. He described and popularized a system whereby a pressure was exerted in the anterior nostril while occluding the opposite side of the nose while the patient vocalized sounds known to close the posterior pharynx. Various forms of this inflation technique are utilized in clinical practice to this date. Patented devices such as those described in Blaine (U.S. Pat. No. 4,817,626), Arick et al. (U.S. Pat. No. 5,419,762), Mendizabal et al. (U.S. Pat. No. 4,749,377), and Strangerup (U.S. Patent No. 5,431,636) utilize one or more forms of the techniques described by Proetz in that they all exert a backward pressure to the Eustachian tube via the nostril and nose. In Arick et al. and Mendizabal, pressure is generated by a compressor powered by an electrical motor. In Strangerup and Elaine the pressure is generated by first closing one nostril and then blowing air through the other nostril into a balloon. All of these devices are fraught with the necessity of inserting a canula into the nose, often of an infected and less than cooperative individual. Nose bleeds often occur through the use of these devices, and the nasal end of the device is considered contaminated. Furthermore, utilization of these devices is normally limited to the privacy of a washroom.
In view of the problems with existing devices, it is therefore desirable to have a device that:
(1) requires only a single, easily performed action by an individual to increase the pressure in the nasopharynx for transmission to the ear via the Eustachian tube without the necessity of inserting any objects into the nasal cavity; PA1 (2) permits variable and increasing pressure resistance for transmission to the nasopharynx depending upon individual user requirements; and PA1 (3) provides psychological and measurable incentives for children who would not otherwise cooperate in inflation of the middle ear.